Collet chuck



March 26,1946;- W. H. CHN-BER 2,397,159

COLLET CHUCK l Filed Nov.` 1945 Patented Mar. 26, 1946 UNITED STATES PATENT oFElcE COLLET CHUCK William IL Schneider, Milwaukee-Wis Application,lflove in berV 6, 1943; Serial No. 50937-1' 7 Claims.. (Cl. 279751) 'llhe invention relatesto collet chucks and Vmore particularly to collet chucks which are used on lathes,`l screw machines, and similar machineA tools.

One object of theinventionis toV provide acollet chuckofcompact construction in` which the collet may be released and tightened while the machine on-which it is used is running and which permits theuse of the full diameter of the spindle bore for the feed through of the stock.

A further object of the invention is to provide acollet type chuck which is readily adjustable to change the position of the collet closing cams or levers to accommodate stockV of different diam-` eters or small changes inthe diameter of thevv stock while using the samecollet.

A further object of thein-vention is to provide a quick closing and opening collet chuck having an adjustable back stopy forY second operation or short length work.

Thel invention further consists` inthe several features hereinafterl set forth and more pari-- ticularly defined by claims at the conclusion,

hereof.

In the drawing:

Fig.- 1 is a view partly in vertical section andV partly in elevation of a chuck embodying the invention;

Fig. 2 is a rear elevation view of the chuck, parts being broken away and parts being shown in section;

Fig. 3 is a detailed end view ofthe closing cam and its mounting;

Fig. 4 is a side elevation view of said cam and its mounting;

Fig'. 5 is a front elevation view of one of thecollets;

Fig. 6 is a side elevation view of the collet shown in Fig.

Fig. '7 is a detailed sectional view of the ad.-

J'ustable back stop andthe chuck collar asso. ciated therewith;

Fig; 8- is a detailed sectional View showing a I41 to receive the threaded colletvengaging/ sleeve- I5 whichis of hardened steel and hasr atapered bore I6; When in use, the sleeve I5 forms ineffect a partof the body Il'l,v butit is made separable in order to permit thechanging ofv collets by the temporary removal of said sleeve I5 and its replacementy after a collethas been insertedy in the chuck. The body I0 has concentric bores I1 and I8l in which a collet-engaging flanged sleeve or collar I`9 is slidably mounted, the flanged end 20 of said sleeve engaging the base portion 2I of'a collet 22.

The collet 22 is a frustro-conical member of spring steel having a straight cylindrical bore or other shape 23 and a tapered outer surface 24 which is of the same taper as the bore I6. The collet; is recessed at circumferentially space d irrtervals by lengthwise extendingrecesses25rwhich extendA from the base for the greater or total part of the length of the collet as shown in Figs. 1 and 6. A slot is cut throughv the collet along" the b ase of each recess, thev s lot 26 starting from the front of the collet for every other recess and terminating a short distance from the rear in a hole or enlargement 21 and the slot 28 starting `from the rear of the collet for the other recesses and terminating in a hole or enlargement 29 at the end of the recess. The recesses and the slots,

provide a relatively short colletvwhose bore' diam;

eter may be contractedby squeezing or forcingr the conical surface 24thereof outwardly relative tothe bore I6 of the chuck body, this actiontakingplace by the forward movement of the collar I9 relative to saidvbody and the reverse movement. or expansion of the collet occurringY when the collar I 9. is permitted to move backwardly.

For moving the` collar* ISL and the collet 2 2 to,

innerbo-res I'V and I8 of saidA body adjacent the collar I9 to permit engagement of thez flange of; said. collar I9 by the shortfarm 35 ofv said lever.` The longer arm 3S ofv each lever 33` projects rear-v wardlyA and has a tapered camming surface 31. whichis adapted to be engaged by the rear edge 38 of an operating ring 39 which is slidably mounted on the cylindrical surface 40 of said chuck body and'y has a ring extension 4I that slidably flts over the adjusting collar or nut 42 and p-revents dirt and chips getting into the chuck operating mechanism. The nut 42 is rotatably mounted on the back plate I3 which projects into. a counter bore 43 in said nut to limit its lengthwise movement in one direction and whichy movement is limited in the other direction by a shoulder 44 formed on the body.V Thus the nut 42 can be turned relative to the'body and its back plate I3, andgit is threaded to engage the threadedY portions V45 Yof each Aclosing lever support 32, so

that turning said nut will cause the'supports 32 to be fed forwardly or backwardly, depending upon the direction of rotation of said mit, in the Y slots 34 to advance or retract the operating posip tion of the levers 30 relative to the collar I9, so that said collar will exert a closing engagement on the collet 22 sooner or later. The nut hasa knurled face 46 to provide a good hand grip.

For holding the adjusting nut 42 in adjusted position, I have shown in Figs. 1 and 2 a series' those conditions it is desirable to positively fix Y the distance that the portion of the work extends into the chuck so as to position the work for fur- Y ther operations, and in this connection it is desirable to provide a positive stop engaged by theV workon its movementto inward position, and for this purpose I have provided the stop structure shown in Fig. 7, in which a ysleeve structure 6I is adapted to be inserted in the Yiianged collar I9 and has a stop rod`or `screw B2 adjustably mounted therein at its inner end, More'particularly, the sleeve structure comprises a rela' tively thick metal ring 53, a thin metal sleeve of recesses 4l formed in the back plate in radially spaced positions and one or more ball bearings t8 forming Va detent adapted to be pressed into any one of the recesses 4'Ibya spring 49 mounted in arbore 4o in the nut 42,. .Y Y

Ithas been noted that'the operating ring 33 is adapted to move rearwardly to move the levers 30 to collet closing position, and conversely a forwardV movement of saidv collar will permit the release of said levers from a holding action on theV collet, which due to its resiliency, will restore the collar I9 and the levers to'their initial or release position shown in Fig, 1. The ring may be moved ingvarious ways'. When the chuck is mounted on a lathe, the ringv is usually moved by a lever 5I which has a yoke portion 52 provided with diametrically disposed shoes 53 engaging in a :groove 54 in said ring and carried by pins 53 mounted in the yoke 52, the lever being pivotally anchored Yto the lathe by a pin or pivot bolt 55 which is carried in a bracket 56 that has a stud portionY 57 adapted to" be mounted in asuitable part of theY head stock of the lathe. When used on 'an -automatic screw machine, the annular groove 540i the collar receivesshoes from a yoke Y- membery which is suitably operatedby the Vusualmechanism of the machine, and Vthis structure has notv been shown, It willalso be understood that lany other'suitable mechanismrfor shifting the collar known in the art can Ybe used.

With this construction, bar stock can be fed v through Vthe Vbore of the spindle of the machine tool in connection withwhich the work is beingY done and through the chuck and the bore of the collet and gripped whenever desired by the rearward movement of the ring 39 which, as'noted Y Y above, causes a contracting 'of the collet through pressure exerted between the collars or sleeves i5V and I`9andon` a forward shifting movement Othe'ringthis pressureA is relieved, so that the Vstock-rnay'againV be r'moved'forjwardly in the collet to itsiiex't position. Y

Instead of using the spring pressed ball detents to lock -the Vnut 42 in various radial positions Y relative "to the chuck body, I may provide one or more screw' bolts 58 mounted in the nut 42 andr having a head adapted to clampingly engageY the back face-of `the back plate I3 as shown in Fig. 8.1 The operating 'clutch ringV 39 maybe slidably keyed tothe chuck body by a key member 59 mountedjin the ring and projecting into va key Vslot El! in the chuckv body I 0.

It is frequently desirable to use chucks of this kind inconn-ection with second operation work or partially turned stock, and in manycases under member 64 welded, braised, or otherwise inte-VV v grally connected to the ring 63 at its forward end and similarly connected to a nut 65 at its rear Y the collar until its inner end abuts said stop inember 62 andwill thenbe in a position for second .Y operation work uponrit, as for instance by the A use of some cutting tool that is Vfed along the work to a denite position.

The back flange plate I3 is providedtwith holes adapted to receive the screws I3', said screws are l provided to hold said iiange. plate to the body I0 andY also prevent it from being unscrewed fromV the thread I2 on'the body.

To prevent the collar I9 and collet 22'rom turning and causing undue wear in the body It)V t Y While vin use, the collar I9 is provided with the securely attached pin 69. y of said pin extends loosely into one of the recesses Y 25 rof the collet, thereby keying saidcollar and colletloosely together. To anchor the collar and collet in said body, the pin 10 as shownin rela` tive position with the collar I9 in Fig. 7 is securely mounted Vin the 'shoulder between the bores" I'I and I8 of the b ody and loosely engages .thel'ioleY or slot in the Bange 2S, thereby keying the said bodyY andcollar together.l

It is to be noted that the bore 23 bf the'coiiet may be other than circular; for example;V it may be of hexagonal, square, or octagonal shape to accommodate stock of suchshape; and it is fur-V Y o ther noted that when this bore isV ofY small size,

that the recesses 25 extend the wholev length of the collet, soY that the wall thickness of the collet at the bases of these recesses is relatively thin to provide the requisite flexibility for operation ofV the collet. Where the recesses extend-thefull length yof `the collet, the slots such as the slots 28 terminate inthe enlargements 29, `but these en-g largements are not at the end of the recesses but are then positioned near the front end of the collet'since the recess extendsthe full length of the collet.

I desire it to be understood that this invention is not to be limitedV to any particular form or arrangement of parts except in so far as such limitations are included in the claims.

What I claim as my invention is: 1. A collet chuck for af collet having a. side surface and a base comprising achuck body,

vsaid chuck body having a part provided with a tapered bore engaging the` tapered side surface of said collet,` a shiftable collarrmounted in said The protruding part Y tapered I body and engaging the base of said collet, a plurality of pivoted collet closing levers engageable with said collar, a separate support for the pivot of each lever adjustably mounted in said chuck body, and a shiftable operating member for moving said levers to collet closing position.

2. A collet chuck for a collet having a tapered side surface and a base comprising a chuck body, a spring collet having a tapered side surface and a base, said chuck body having a part provided with a tapered bore engaging the tapered side surface of said collet, a shiftable collar mounted in said body and engaging the base of said collet, a plurality of pivoted collet closing levers engageable with said collar, a separate support for the pivot of each lever slidably mounted in said chuck body and having a threaded portion, a manually adjustable nut rotatably mounted on said chuck body and engageable with the threaded portions of said supports to advance or retract the same relative to said collar, means for securing said nut to said body in different positions of adjustment and means for simultaneously moving all of said levers to collet closing position.

3. A collet chuck for a collet having a tapered side surface and a base comprising a hollow chuck body having a part provided with a tapered bore engaging the tapered side surface of said collet and a plurality of radially disposedlengthwise extending slots in its peripheral portion, a shiftable collar slidably mounted in said body and engaging the base of the collet, said body having concentric bores in which said collar operates,

one of said bores communicating with said radially disposed slots, a lever support slidably mounted in each of said slots and keyed thereby to said body, a multiplying lever pivotally mounted on each of said supports, the shorter arms of said levers engageable with said collar, and a sleeve member slidably mounted over the outer portion of said body and having a camming engagement with the longer arms of said levers.

4. A collet chuck for a collet having a tapered side surface and a base comprising a hollow chuck body having a part provided with a tapered bore engaging the tapered side surface of said collet and a plurality of radially disposed lengthwise extending slots in its peripheral portion, a shiftable collar slidably mounted in said body and engaging the base of the collet, said body having concentric bores in which said collar operates,

one of said bores communicating with said radially disposed slots, a lever support slidably mounted in each of said slots and keyed thereby to said body, a multiplying lever pivotally mounted on each of said supports, the shorter arms of said levers engageable with said collar, and a sleeve member having camming engagement with the longer arm of said levers slidably mounted over the outer portion of said body and completely covering said slots in all of its operating positions.

5. A collet chuck for a collet having a tapered side surface and a base comprising a hollow chuck body having concentric inner bores With a tapered bore communicating with one of said concentric bores and engageable with the tapered side surface of the collet and a plurality of radially disposed lengthwise extending slots in its peripheral portion communicating with the larger of said concentric bores, said body portion also having a back plate, a nut mounted to rotate on said back plate and having a forwardly extending cylindrical portion, a shiftable collar slidably mounted in said body within said concentric bores and engageable with the base of the collet, a lever support slidably mounted in each of said slots and keyed thereby to said body, each lever support having a threaded portion engageable with said nut, means for securing said nut in different angular positions relative to said body to thereby secure said supports in different longitudinal displacements relative to said body, a multiplying lever pivotally mounted on each of said supports, the shorter arms of said levers engageable with said collar, and a sleeve member having camming engagement with the longer arms of said levers slidably mounted over the outer portion of said body and the cylindrical portion of said nut and completely covering said slots in all of its operating positions.

6. In a collet chuck, thecombination with a chuck body and a shiftable collar mounted in said body and cooperating therewith to contract a collet about the work, of a plurality of pivoted collet closing levers engageable with said collar, a separate support for the pivot of each lever lengthwise slidably mounted in said body, a collar rotatably mounted on said body and operatively connected to the pivot supports for said levers to vary the position of said levers relative to said shiftable collar, means for locking said rotatable collar to said body in diierent positions of adjustment, and means for simultaneously moving all of said levers to collet closing position.

7. In a collet chuck, the combination with a chuck body and a shiftable collar mounted in the body and cooperating therewith to contract a collet about the Work, of a plurality of pivoted collet closing levers engageable with said collar, a separate support for the pivot of each lever lengthwise -adjustably mounted in said chuck body, means for adjusting the positions of said separate supports relative to said collar, and a shiftable operating member for moving said levers to collet closing position.

WILLIAM lII. SCHNEIDER. 

